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The prevalence of peanut allergy among children tripled between 1997 and 2008, researchers found.

Respondents to a telephone survey reported that 1.4% of children had peanut allergies, up from just 0.4% a decade earlier, Scott Sicherer, MD, of Mount Sinai School of Medicine in New York City, and colleagues reported in the May 12 issue of the Journal of Allergy and Clinical Immunology.

"Although the total population prevalence of self-reported peanut and/or tree nut allergy did not increase among adults since 1997, there was a significant rise in self-reported allergies among children," the researchers wrote.

They conducted the phone survey in 2008 and compared those results with two prior surveys they had done -- one in 2002 and the other in 1997.

Peanut and tree nut allergies are the leading causes of fatal allergic reactions and are not typically outgrown, the researchers noted.

In 2008, the researchers surveyed 5,300 homes, which included a total of 13,534 individuals.

They found that the prevalence of combined peanut and tree allergies among children was 2.1%, compared with 0.6% in 1997.

For peanut allergy alone, prevalence was 1.4%, compared with just 0.4% in 1997.

Allergies to tree nuts alone increased to 1.1% in 2008, up from 0.2% in 1997.

Tree and peanut allergies remained steady among adults, at a rate of 1.3%.

The researchers also noted that the prevalence of peanut allergy among U.S. children is similar to estimates from Canada, Australia, and the U.K.

Its increase could be attributable to the "hygiene hypothesis" -- the idea that less exposure to allergens and bacteria in childhood leave the immune system underdeveloped and vulnerable, the researchers speculated.

Or it could be the timing of when the food is introduced, or how the food is prepared, the researchers said. Roasted peanuts, for instance, have increased allergenicity because cooking changes the nature of the proteins in the nut.

Either way, the prevalence "represents a significant health burden," and the researchers called for better strategies for prevention and treatment, "particularly if we will be seeing a significant increase of these persistent allergies with time."

The study was limited by self-report and problems with identifying "true" allergy.

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